looking at the buy it now price ($75.00 + shipping) I wouldnt go for it as the J-Pac is available from ultimarc for $57 + shipping.
The J-pac is a much better known product and also has plenty of documentation kicking around.
there seems very little if any info on the ebay one, even the sellers site doesnt list it as a product they sell or offer any information on it.
and what the heck is it using the parallel port for?